Embodiments of the disclosed technology relates to a polymer dispersed liquid crystal film and a method for manufacturing the same.
A liquid crystal display with polymer dispersed liquid crystal (PDLC) film is a recently-developed flat display device capable of displaying information. PDLC film is a novel light-controlled film, which is formed by dispersing small molecular liquid crystals in a polymer matrix in the form of droplets and can exhibit two different optical state, transmission and scattering, under the effect of an external field (such as electric field, thermal field, etc.).
In a PDLC film, nematic liquid crystals are uniformly dispersed in a solid-state organic polymer matrix in micron scale. When no voltage is applied, each liquid droplet has its optical axis in a preferred orientation, i.e., the optical axes of all microparticles are in a state of disorder orientation. Because liquid crystal is a strongly anisotropic material optically and dielectrically, its effective refractive index is not matched with the refractive index of the matrix, in which case incident light may be strongly scattered, so that it exhibits an opaque or translucent opalescence. When an external electric field is applied, the orientation of the optical axes of the nematic liquid crystal molecules turns uniformly along the direction of the electric field. The ordinary refractive index of the liquid crystal microparticles reaches a certain extent of match with the refractive index of the matrix. Light can pass through the matrix, so that it exhibits a transparent or translucent state. When the external electric field is removed, the liquid crystal microparticles return to the initial state of light scattering. Therefore, the PDLC film possesses properties of an electrically controlled light switch under the effect of an electric field.
However, during the manufacture of PDLC films, it occurs often that ITO plastic films are in a state of disengagement or semi-disengagement because the cohesive force between the interposed PDLC film and the two ITO plastic films above and under the PDLC film is weak. In this way, when an electric field is applied to the PDLC film, many abnormal situations such as poor contact will occur, which brings huge difficulties to large-scale industrial manufacture. It not only lowers the displaying quality and performance of the product, but also severely affects the yield and economic benefit of the product.